Make cairo components conditional on the relevant libaries etc existing.

SConstruct

@@ -124,7 +124,9 @@ for prereq in ('BOOST', 'PNG', 'JPEG', 'TIFF', 'PGSQL', 'PROJ', 'GDAL',):
     
 env.ParseConfig(env['FREETYPE_CONFIG'] + ' --libs --cflags')
    
+if env.Execute('pkg-config --exists cairomm-1.0') == 0:
     env.ParseConfig('pkg-config --libs --cflags cairomm-1.0')
+    env.Append(CXXFLAGS = '-DHAVE_CAIRO');
 
 if env['XMLPARSER'] == 'tinyxml':
     env.Append(CXXFLAGS = '-DBOOST_PROPERTY_TREE_XML_PARSER_TINYXML -DTIXML_USE_STL')

bindings/python/SConscript

@@ -25,7 +25,9 @@ import os
 
 Import('env')
 
+if env.Execute('pkg-config --exists pycairo') == 0:   
     env.ParseConfig('pkg-config --cflags pycairo')
+    env.Append(CXXFLAGS = '-DHAVE_PYCAIRO');
 
 prefix = env['PYTHON_PREFIX'] + '/' + env['LIBDIR_SCHEMA'] + '/python' + env['PYTHON_VERSION'] + '/site-packages/'
 install_prefix = env['DESTDIR'] + '/' + prefix

bindings/python/mapnik_python.cpp

@@ -58,14 +58,18 @@ void export_projection();
 
 #include <mapnik/map.hpp>
 #include <mapnik/agg_renderer.hpp>
+#ifdef HAVE_CAIRO
 #include <mapnik/cairo_renderer.hpp>
+#endif
 #include <mapnik/graphics.hpp>
 #include <mapnik/image_util.hpp>
 #include <mapnik/load_map.hpp>
 #include <mapnik/config_error.hpp>
 #include <mapnik/save_map.hpp>
 
+#ifdef HAVE_PYCAIRO
 #include <pycairo.h>
+#endif
 
 void render(const mapnik::Map& map,mapnik::Image32& image, unsigned offset_x = 0, unsigned offset_y = 0)
 {
@@ -79,6 +83,8 @@ void render2(const mapnik::Map& map,mapnik::Image32& image)
     ren.apply();
 }
 
+#ifdef HAVE_PYCAIRO
+
 void render3(const mapnik::Map& map,PycairoSurface* surface, unsigned offset_x = 0, unsigned offset_y = 0)
 {
     Cairo::RefPtr<Cairo::Surface> s(new Cairo::Surface(surface->surface));
@@ -93,6 +99,8 @@ void render4(const mapnik::Map& map,PycairoSurface* surface)
     ren.apply();
 }
 
+#endif
+
 void render_tile_to_file(const mapnik::Map& map, 
                          unsigned offset_x, unsigned offset_y,
                          unsigned width, unsigned height,
@@ -176,8 +184,10 @@ BOOST_PYTHON_MODULE(_mapnik)
     def("render_tile_to_file",&render_tile_to_file);
     def("render",&render); 
     def("render",&render2);
+#ifdef HAVE_PYCAIRO
     def("render",&render3);
     def("render",&render4);
+#endif
     def("scale_denominator", &scale_denominator);
     
     def("load_map", & load_map, load_map_overloads());

bindings/python/python_cairo.cpp

@@ -21,6 +21,8 @@
  *****************************************************************************/
 //$Id$
 
+#ifdef HAVE_PYCAIRO
+
 #include <boost/python/type_id.hpp>
 #include <boost/python/converter/registry.hpp>
 
@@ -46,3 +48,11 @@ void register_cairo()
 
    boost::python::converter::registry::insert(&extract_surface, boost::python::type_id<PycairoSurface>());
 }
+
+#else
+
+void register_cairo()
+{
+}
+
+#endif

src/SConscript

@@ -43,7 +43,6 @@ else: # Linux and others
 source = Split(
     """
     agg_renderer.cpp
-    cairo_renderer.cpp
     datasource_cache.cpp
     envelope.cpp
     filter_factory.cpp
@@ -79,7 +78,11 @@ source = Split(
     """
     )
 
-#source.append("cairo_renderer.cpp")
+if 'cairo' in env['LIBS']:
+    source += Split(
+        """
+        cairo_renderer.cpp
+        """)
 
 if env['XMLPARSER'] == 'tinyxml':
     source += Split(